METHOD FOR ROLLING CONTINUOUSLY CAST BILLET OF FERRITIC STAINLESS STEEL CONTAINING NIOBIUM AND COPPER

摘要

PURPOSE:To prevent cracking by forming a continuously cast billet of a ferritic stainless steel having a specified composition contg. Nb and Cu, cooling the billet to a specified temp. under specified cooling conditions, and reheating and hot rolling it. CONSTITUTION:A continuously cast billet of a ferritic stainless steel contg. Nb and Cu is formed. The steel consists of, by weight, 0.05% C, 0.04% N, 10-30% Cr, 1% Si, 1% Mn, 0.2-1% Nb [Nb% =8X(C%+N%)], 0.2-2% Cu and the balance Fe with inevitable impurites. The billet is cooled from 700 deg.C to 200 deg.C at =18 deg.C/hr average cooling rate, and it is cooled from 400 deg.C to 200 deg.C at =15 deg.C/hr average cooling rate. The billet is heated again without cooling to 200 deg.C, and it is hot rolled.